1. Field of the Invention
The present invention relates to a circuit layout and corresponding circuit structure, and more particularly, to a symmetricelectrical connection system.
2. Description of the Prior Art
As all kinds of electronic devices advance in their functions and operation speed, therefore accuracy control of specific components in the electronic devices becomes an important issue. Symmetric circuits such as differential circuits rely on their own symmetry so that the strict accuracy control of symmetrically installed components in the symmetric circuits is achieved. However, impedances such as parasitic capacitances, induced by circuit layouts and superposing the impedances of the symmetrically installed components, vary from structures to structures. Therefore, the resultant impedances of the symmetrically installed components cannot fill the symmetry requirement of the original design. As a result, the electronic devices using the above-mentioned symmetric circuits cannot meet predetermined specifications of the original design.
Please refer to FIG. 1 showing a circuit layout diagram of an electrical connection system 100 according to the prior art. The symmetrically installed capacitors C1, C2 are examples of the above-mentioned symmetrically installed components. The lower-left and upper-right rectangular regions shown in FIG. 1 are sub-structures composing the capacitor C1. The lower-right and upper-left rectangular regions shown in FIG. 1 are sub-structures composing the capacitor C2. Wherein the capacitance of the capacitor C1 is equal to the capacitance of the capacitor C2.
As a result of the above-mentioned symmetry requirement of the symmetrically installed components, the electrical connection system 100, for connecting the sub-structure of capacitor C1 at a first node 101 to the sub-structure of capacitor C1 at a third node 103 and for connecting the sub-structure of capacitor C2 at a second node 102 to the sub-structure of capacitor C2 at a fourth node 104, is common in many circuits. Please refer to FIG. 2 showing a three-dimensional diagram of the circuit structure of the electrical connection system 100 in FIG. 1. However, the structure of the electrical connection system 100 is asymmetrical so that the parasitic capacitance of the capacitor C1 (the capacitance induced by the system 100 and superposing the capacitance of the capacitor C1) is different from the parasitic capacitance of the capacitor C2 (the capacitance induced by the system 100 and superposing the capacitance of the capacitor C2). Therefore, the resultant impedances of the symmetrically installed components (the capacitors C1, C2) are different from each other. As a result, the symmetric circuits of this kind degrade in performance.
In conclusion, the structure of the electrical connection system 100 is asymmetric so that the structure of the combination of the electrical connection system 100 and the symmetrically installed components outside the system 100 is also asymmetric. Accordingly, the parasitic capacitances induced by the system 100 and superposing the capacitance of the symmetrically installed components are different from each other so that the resultant impedances of the symmetrically installed components are different from each other. As a result, the symmetry of the symmetrically installed components is wasted and the symmetric circuits of this kind degrade in performance.